Tobacco sheet material and method of forming



Nov. 6, 1956 D. BANDEL 2,769,734

TOBACCO swam MATERIAL AND METHOD OF FORMING Filed July 14, 1955 CLEAN0nd CLASSIFY TOBACCO DRY GRIND TOBACCO WATER MINGLING TOBACCOPREPARATION PARTICLES WITH 0f ADHESIVE WATER 0nd ADHESIVE FORMINGTOBACCO 0nd ADHESIVE INTO A SHEET ROLL of FINISHED TOBACCO SHEETADJUSTING MOISTURE CONTENT of SHEET MATERIAL ENDLESS FORMING SURFACEINVENTOR. David BundeI ATTOR NEY of this invention. been made by theapplication of a layer of tobacco dust United States Patent Ofiice2,769,734 Patented Nov. 6, 195

TOBACCO SHEET MATERIAL AND METHOD OF FORMING 'David'BandeL Stamford,Comp, assignor to International .Cigar Machinery Company, a corporationof New Jersey Application July 14, 1955,'Se'rial No. 522,162

24 Claims. (Cl. 13115) This application is a continuation-in-part ofcopending application Ser. No. 477,111 filed December 22, 1954, nowabandoned.

This invention relates to self supporting tobacco sheet material and toa method of forming it. This invention further relates to improvedsmoking articles made with such a product. Particularly, the inventionrelates to a substantially water resistant tobacco sheet materialcharacterized by the aroma, color, taste and burning characteristics ofnatural whole leaf tobacco.

Heretofore, diiferent kinds of tobacco sheets have been made by variousmethods. Paper making techniques have been employed in which tobacco ispulped in a large quantity of water and many of the desirable elementsof natural tobacco such as flavors are leached away. To-

bacco has been wet ground to a colloidal paste and then cast-into sheetswhich do not burn as well as the product Laminated tobacco products havealso the primary characteristic required of such agents is'that "courseof manufacturing and so be self supporting. It =-rnust alsohold togetherwell in smoking products such as cigars, cigarettes, or pipe tobacco.

Preferably, it should have at least the tensile strength of natural leaftobacco.

Moreover, the tobacco sheet material should be'flexible. The tobaccoshould resist disintegration by moisture and 'have wet strength so asnot to gum up upon blending, casing and similar treatment as well aswhen used ulti- 'mately in smoking or chewing. The film forming agentshould be easy to handle, should be chemically stable,

should be in a convenient form, and should require little specialtreatment to prepare it for final use.

Heretofore, nohomogeneous (non-laminated) self supporting, substantiallywater resistant, tobacco sheet material which burns with the desirablecharacteristics of natural tobacco has been made. Homogeneous materialis made by a suspension rather than a laminating method.

Accordingly, it is an object of this invention to promatrix fordispersed tobacco particles.

ferred range is between 1% and 20%.

centipoises.

vide a self supporting, moisture resistant, tobacco sheet material whichis-easily worked into a smoking product and which has substantially thenatural characteristics of tobacco including taste, color and aroma.

A "further object of this invention is to provide a method of forming aself supporting, moisture resistant, tobacco sheet material which iseasily worked into a smoking product and which has substantially thenatural characteristics of tobacco including taste, color and aroma.

These and other objects and advantages of the inven- "tion areelaborated and set forth in the following descriptron.

The advantages of the present invention are realized by mixing with anadhesive film forming agent, which may be dispersed in water, and whichis adaptable to the formation of a water resistant sheet, a quantity -offiiiely dividedtobacco, to'form a viscous suspension, and

forming this suspension into a dry tobacco sheet. Filler 'rnaterialfandfibers may also be incorporated with the binder.

cedure for the manufacture of tobacco sheet material according'to thisinvention.

In tobacco sheet material prepared according to this invention, theadhesive film forming agent serves as 'a These particles are imbeddedinthe adhesive material. This material is formed from a slurry or mixtureof tobacco particles and While both laminated and imbedded in theadhesive matrix. For example, sheets which have only a surface coatingof tobacco particles over a film or layer of adhesive which isinternally free from tobacco are clearly laminated fo'rms, whereassheets which include tobacco particles entirely surrounded by adhesivematerial as Well as a surface coating of tobacco are of the homogeneoustype.

The adhesive formulation may include intermingled 'fifibers to addstrength to the tobacco sheet or optionally fibers may be omitted. Somesuitable organic fibers are polysaccharides such as cellulose pulp inthe form of cigarette paper pulp or 'glassine paper pulp. Mineral fibersare also suitable such as asbestos or glass fibers.

The fibrous material is suspended with the adhesive film forming agents,preferably in a small quantity of water.

The fibrous material and also the selected adhesive film forming agentsare of a composition which when burned in the smoking article do notadversely affect the blandn'ess, flavors, aroma or burning qualities ofthe tobacco. This characteristic is described as being bornpatible withtobacco.

In the finished tobacco sheet the adhesive formulation may be between0.5% and 33% by weight but a pre- The viscosity of theformulation,measured on a Brookfield viscometer should be between 500 and 5,000,000centipoises. The preferred viscosity range is between 6,000 and 20,000The adhesive film forming agent or binder is selected to impart to thefinished dry tobacco sheet material a high degree of moistureresistance. The preferred film forming agent is a polysaccharide and isusually water dispersible in the first step of the method of forming thesheet according to this invention. When the adhesive film forming agentis provided in the form of other molecules.

dry powder, particle sizes used in this invention are preferably similarin size to the tobacco particles and may be smaller. Cellulose glycolicacid (acid form of carboxymethyl cellulose) is a preferred film formingmaterial since the dried cellulose glycolic acid is subsetantiallyinitially water resistant. Hydroxyethyl carboxymethyl cellulose,viscose, and galactomannan gum dispersions as well as water insolublealgin compounds when properly formulated are other polysaccharides whichcan be used. Polyuronides include all uronic acid containingpolysaccharides such as pectins and pectin derivatives, pectates,pectinates, pectinic acid and pectic acid forms as well as algins, alginderivatives, alginates and alginic acid forms. Polyuronides such aspectins may also be used. In particular water insoluble pectates such ascalcium and magnesium pectate are valuable adhesives. Any of thesematerials may also be used to form laminated tobacco sheets by methodssimilar to those described in copending applications S. N. 124,042, S.N. 220,174 and S. N. 262,575, now respectively U. S. Patents 2,734,510

and 2,734,513 and 2,734,509, all issued February 14, 1956.

Adhesive film forming materials used in this invention may be variouslydistinguished as either soluble, substantially insoluble, waterresistant and initially water insoluble. A true solution is regarded asa complete dispersion of particles on a molecular level wherein eachmolecule is individually completely disassociated from Substantiallyinsoluble materials have such a low degree of solubility as to appearunder all ordinary conditions of tobacco use to be insoluble and thesematerials maintain a self supporting film coherence even whencompletely. wetted by water, saliva or ordinary casing solutions for apractical working span of time and indeed will hold together even whilecompletely immersed. Water resistant materials have a wet strengthbetween soluble materials, such as methyl cellulose, and substantiallyinsoluble materials, such as cellulose glycolic acid. Initially waterinsoluble material does not form a true solution but may be applied in agelatinous and dispersed condition to tobacco particles. On the otherhand, initially soluble materials such as the sodium salt ofcarboxymethyl cellulose can be converted to ultimately insoluble formsafter a tobacco sheet is formed by the application of insolubilizingagents such as acids or metal salts which can convert the adhesive to aninsoluble form. Initially insoluble polysaccharide adhesive material isless than freely soluble at at least one stage in the manufacture oftobacco sheet material prior to the final sheet forming opera-tion.

The film forming agent is the structural foundation of the sheet. If thefilm forming agent is weak or discontinuous, the sheet will crumble anddisintegrate into dust when handled in tobacco machinery. When tobaccosheet material is fed from continuous rolls into automatic cigar makingequipment, its crimping and setting properties may be criticallyimportant. Tobacco sheet material made according to this inventionproduces desirable crimping and setting properties for use in automaticcigar making machines and other machinery for fabricating tobaccosmoking articles. 7

The tobacco can be from either leaves or stems and need not be byproductmaterial although one of the economic advantages of the invention is theutilization of otherwise useless fine quality tobacco which oftencrumbles from the leaves during ordinary processing.

The preferred finished sheet has a tensile strength and thicknessapproximately that of natural leaf tobacco. Of

course, the strength and sheet thickness may be adjusted for particularapplications. A preferred thickness range is between .002 and .011.Tensile strength may be, for example, about 400 grams per inch onmaterial .003" thick. The sheet is self supporting and coherent evenafter immersion in water. This feature may be defined so that at leastone square foot of material has this property.

The finely divided or fragmented tobacco may be prepared by grinding orby other fragmenting means. For example, dust may be used. Sheet madeentirely of dry ground tobacco is a preferred form of the invention.Tobacco which is entirely dry ground is tobacco which has not undergonecomminution in the presence of excess liquid, such as a wet milling.Satisfactory tobacco sheets can be made from finely divided tobaccowhich will pass through a 20 mesh screen and will be mostly retained bya 325 mesh screen. A preferred particle size range is between 60 and 250mesh. Small tobacco particles appear to burn more evenly than largeparticles. However, while colloidal tobacco may be used for a minor partof the blend, preferably the larger designated particle sizes areemployed as these tend to give a better burning sheet.

Tobacco sheet material prepared according to this invention haspreferably a moisture content in the range between 8% and 24%. Aparticularly desirable range of moisture content in cigarette tobacco is9% to 13% and in cigar binder 16% to 22% on a dry tobacco basis.

Some inorganic fillers which may be used in powder form, for example,with tobacco sheet material are kaolin and Fullers earth. Among suitableorganic fillers are various cellulosic preparations. Fillers may rangefrom 2% to 15% by weight of the finished sheet. Various food dyes mayalso be used in manufacturing the tobacco sheets and foils.

Finely divided tobacco which is prepared, for example, as describedabove, is mingled with an adhesive formulation which may include fibersto form a slurry or a suspension. A minimal quantity of water isemployed in the adhesive formulation to avoid leaching solubles from thetobacco. The viscosity of the slurry is controlled by the relativeamount of water, tobacco and adhesive used. To promote the mingling oftobacco particles and film forming agent, the slurry is agitatedthoroughly until all the particles are completely wetted. Mixing mayconveniently be done in a ball mill. The exact relation of ball size andvolume to total volume of the mixing chamber will depend upon severalfactors such as viscosity, particle size of tobacco and proportion ofadhesive material solids to tobacco.

Alternatively, the tobacco particles and dry adhesive (with or withoutfibers) may be mixed together and a slurry formed with the mixed dryparticles. The product of either method may be applied to a belt, bycasting or spraying for example, to form a coating film which is thendried and removed in a continuous sheet.

The viscous slurry can also be shaped and formed into a sheet bycalendering, extrusion or molding, when the viscosity is very high.

Drying the wet material is a part of the sheet forming operation and isnecessary in most cases to achieve substantial water resistance. Themoisture content of the sheet can be adjusted by conventional tobaccotreatlng methods. The finished dried sheet may be conveniently handledin roll form.

The tobacco sheet of this invention has many useful applications andsmoking articles such as cigars, cigarettes, pipe tobacco as well aschewing tobacco made in whole or in part from this sheet material, arepart of the invention. The sheet material may be fed from rolls toautomatic machines, for example, cigar machines, for use as a binder orwrapper.

ticizer and a cross-linking agent.

*liquid and a firm paste. tobaccowas added to nine parts of binderdispersion.

- as a finished sheet.

-A; preferred example of a method in -accordance-with thepresentinvention of making a substantially water insoluble-self; supportingtobacco sheet material was. carried out as follows: Tobacco was cleanedof foreign matter and comminuted to pass through an 80 mesh screen. Thesize reduction was conveniently carriedout in a ball mill.

A preferred polysaccharide film forming agent was prepared by dissolving2.6 pounds of sodium carboxymethyl cellulose in 174 pounds of water. Tothe solution 2.5

pounds of paper. pulp wereadded and dispersed together The suspensionwas applied to a stainless steel belt, where it was spread out, dried,remoistenedand removed The drying operation was the final step in fixingthe binder in a substantially water insoluble form.

EXAMPLE TWO Binder mixture Parts Locust bean gum 2 Water 100' Glycerinep 0.6 Glassine pulp -a 2 The locust bean gum, a galactomannan gumderivative from legume endosperm, was sprinkled into cold water withagitation. good agitator for this purpose, although other types of ACowles dissolver was foundzto be a agitators also produce good results.After two hours agitation in cold water, the gum dispersion was heatedto l70200 F. with continued agitation and held above 170 F. for thirtyminutes. Glycerine and glassine pulp vwerefthen mixed in. After:cooling, 12 parts of. ground tobacco dust passing through an 80 meshscreen were mixed in. The tobacco-binder suspension was then passedthrough a colloid mill set at low .-'clearance,.i. e. .002-:.010inchesusing onepass at .010 inches. and a second pass at .002 inchclearance. The viscosity of the final tobacco-binder suspension was12,400 lcentipoises at 85 F. and the pH was 6.4. The suspension was caston a stainless steel belt, dried and remoistened by a fine water sprayto the point where a continuous sheet of tobacco could be removed fromthe casting belt.

EXAMPLE THREE Binder mixture Parts Hydroxyethyl cellulose (HEC) 3 Water100 Filler paper pulp 1.5 Glycerine 0.3 Glyoxal 1.0

All materials were charged into a vessel equipped with an agitator andagitated for one hour. A Cowles dissolver is suitable for agitationpurposes. Sixteen parts of finely ground cigar binder leaf scrap passingthrough an 80 mesh sieve were added and the tobacco-binder suspensionwas agitated for thirty minutes. The viscosity of the tobacco-bindersuspension was 6500 centipoises, and the pH was 6.0.

The tobacco binder suspension was sprayed onto a moving stainless steelcasting belt, dried and carefully water.

.rsmqis nsd i spenn tiemoy l tr e-tpba ;she ti a s9 mu s P o e --It wasdesirable-to reduce thesuspension pHto to obtain better resistance todisintegration; ion soaking in Lower. pH'increases the rateofcrosslinking of the HEC by' glyoxal, and thus increases waterresistance.

- EXAMPLE FOUR Binder mixture Parts Sodium alginate, low viscosity(Kelgin LV) ..2 Glycerine 0.6 Water 90 Cigarette paper pulp fiber 2 Thesodium alginate was-agitated in thewateruntil completely dissolved.'Tothis was added a-solutionof :0.4 parts calcium chloridetdissolved in10zparts water. On. addingthe calcium chloride,.lumps of gelatinouscalcium alginate precipitated. As agitation continued'these lumps brokeup and the entiremassbecamea uniform .gel. .After this gel waspassedsthrough a colloid mill-.at

-a 0.001 inch clearance itwas a smooth' dispersion of insoluble calciumalginate in a highly hydratedform. i It is desirable to restrict theaddition of calcium chloride to 50-90% of the stoichiometric.equivalentof sodiumalginate to obtain a.-good balance between stability of'the:dispersionandwater resistance of the dried film. Ifthecalciumequivalent. added. exceeds the dispersion tends to belumpyanddoesnot produce a smoothfilm.

..When the added calcium equivalentis less'than 50% of the .sodiumalginate, the'dried filmtends to. be sensitive-.10

water and to disintegrate on wetting. .The..fibers.were

:then t-horoughlymixed into sthe -binder dispersion. .So-

dium-pectate may .be substituted conveniently for sodium alginate andpropylene glycol alginate may also be used. ".To :the binder dispersion.prepared above, eight parts of groundtobacco, minus .80 mesh, were added.to; form a suspension. The suspension .was, passed through a col- .loidmill twice. inch and the second: pass was at a clearance setting of Onepasswas ata clearance of. 0.01

smoking articles. vThe material is resilient, substantially waterinsoluble,- self supporting and retains thequ'alities of natural-tobaccoleaf such asaroma, flavor and color.

The process is'based upon the'blending of fincly divided tobaccoandasuhstantiallywater insoluble film forming agent to format novel tobaccosheet material.

What is claimed is:

1. Tobacco sheet material comprising finely divided tobacco, at least aportion of which is entirely dry ground, within a matrix of an initiallywater insoluble polysaccharide adhesive.

2. Tobacco sheet material comprising finely divided tobacco, at least aportion of which is entirely dry ground, and randomly dispersed fibers,within a matrix of substantially water insoluble polysaccharide.

3. Tobacco sheet material comprising finely divided tobacco, at least aportion of which is entirely dry ground, within a matrix of at least oneadhesive material selected from the group consisting of carboxymethylcellulose, hydroxyethyl cellulose, galactomannan gums and substantiallywater insoluble polyuronides.

4. Tobacco sheet material comprising finely divided tobacco within amatrix of cross-linked polysaccharide adhesive.

5. Tobacco sheet material comprising finely divided tobacco within amatrix of polysaccharide adhesive and glyoxal.

6. Tobacco sheet material comprising finely divided tobacco, at least aportion of which is entirely dry ground, within a matrix of celluloseglycolic acid.

7. Tobacco sheet material comprising finely divided tobacco, at least aportion of which is entirely dry ground, randomly dispersed non-tobaccofibers, within a matrix of cellulose glycolic acid. 8. Tobacco sheetmaterial comprising finely divided tobacco, at least a portion of whichis entirely dry ground which will pass through a 20 mesh screen, andpaper pulp fiber within a matrix of cellulose glycolic acid.

9. Tobacco sheet material comprising finely divided tobacco within amatrix of glyoxal and hydroxyethyl cellulose.

10. Tobacco sheet material comprising finely divided tobacco imbedded inan initially water insoluble algin compound.

11. Tobacco sheet material comprising finely divided tobacco imbedded incalcium alginate.

12. Tobacco sheet material comprising finely divided tobacco imbedded inan initially water insoluble pectin derivative.

13. Tobacco sheet material comprising finely divided tobacco which willpass through 20 mesh screen and cellulose fiber, within a matrix ofglyoxal and hydroxyethyl cellulose.

14. Tobacco sheet material comprising finely divided tobacco andrandomly dispersed fibers, imbedded in an initially water insolublealgin compound.

15. Tobacco sheet material comprising finely divided tobacco andrandomly dispersed fibers, imbedded in an initially water insolublepectic acid compound.

16. Tobacco sheet material comprising finely divided tobacco andrandomly dispersed fibers, imbedded in an initially Water insolublepolyuronide.

17. Tobacco sheet material comprising finely divided tobacco andrandomly dispersed fibers, imbedded in calcium alginate.

18. Tobacco sheet material comprising finely divided tobacco inassociation with propylene glycol alginate.

19. The method of forming tobacco sheet material which comprises formingin a liquid a suspension of finely divided tobacco, at least a portionof which is entirely dry ground, and an initially water insolublepolysaccharide adhesive, applying said suspension to a forming surface,drying said suspension to form tobacco sheet material and removing saidtobacco sheet material from said forming surface.

20. The method of forming tobacco sheet material which comprises formingin a liquid a viscous suspension of finely divided tobacco, at least aportion of which is entirely dry ground, and an initially Waterinsoluble polysaccharide adhesive, calendering said suspension to form atobacco sheet and drying said tobacco sheet.

21. The method'of forming tobacco sheet material which comprises formingin a liquid a viscous suspension of finely divided tobacco, at least aportion of which is entirely dry ground, and an initially waterinsoluble polysaccharide adhesive, extruding said suspension to formtobacco sheet material and drying said sheet material.

22. The method of forming tobacco sheet material which comprises formingin a liquid a suspension of finely divided tobacco, at least a portionof which is entirely dry ground, randomly dispersed non-tobacco fibersand an initially water insoluble polysaccharide, applying saidsuspension to a forming surface, drying said suspension to form tobaccosheet material and removing said tobacco sheet material from saidforming surface.

23. The method of forming tobacco sheet material which comprises formingin a liquid a suspension of finely divided tobacco, at least a portionof which is entirely dry ground, randomly dispersed non-tobacco fibersand cellulose glycolic acid, applying said suspension to a formingsurface, drying said suspension to form tobacco sheet material andremoving said tobacco sheet material from said forming surface.

24. The method of forming tobacco sheet material which comprises addingto an aqueous suspension of cellulose glycolic acid and paper pulp fibera quantity of finely divided tobacco, at least a portion of which isentirely dry ground, which will pass through 20 mesh screen, disposingsaid suspension upon an impermeable forming surface, drying saidsuspension to form tobacco sheet material and removing said tobaccosheet material from said forming surface.

References Cited in the file of this patent UNITED STATES PATENTS888,743 Rogers May 26, 1908 2,433,877 Wells et a1. Jan. 6, 19482,592,553 Frankenburg Apr. 15, 1952 2,592,554 Frankenburg Apr. 15, 19522,598,680 Frankenburg June 3, 1952 2,613,673 Sartoretto et al. Oct. 14,1952 2,708,175 Samfield et al May 10, 1955 2,734,509 Jurgensen Feb. 14,1956 2,734,510 Hungerford et a1. Feb. 14, 1956 2,734,513 Hungerford etal Feb. 14, 1956 2,747,583 Frankenburg et al May 29, 1956 FOREIGNPATENTS C. L. Mantell: Water Soluble Gums, published 1947 by ReinholdPublishing Corporation, New York, N. Y., pages 124 and 125.

1. TOBACO SHEET MATERIAL COMPRISING FINELY DIVIDED TOBACCO, AT LEAST APORTION OF WHICH IS ENTIRELY DRY GROUND, WITHIN A MATRIX OF AN INITIALLYWATER INSOLUBLE POLYSACCHARIDE ADHESIVE.